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6.Command Specification LOG SENSE
6-30 SONY AIT-5 drive SDX-1100V series Ver.1.0
6.6.11. Data Compression Transfer Log Page (39h) (Sony Unique)
The page allows the initiator to monitor the performance of the ALDC compression. The PC field in LOG SENSE
determines whether current cumulative or current/default threshold values are returned. The page has the
following format:
Table 6-34: Data Compression Transfer Log Page
Bit
Byte
7 6 5 4 3 2 1 0
0 Reserved Page Code (39h)
1 Reserved
2 (MSB) Page Length (58h)
3 (LSB)
4 (MSB) Parameter Code (n)
5 (LSB)
6 DU (0) DS (1) TSD (0)
ETC (0)
TMC (00) LBIN (0) LP (0)
7 Parameter Length (4)
8 (MSB) Parameter Value
11 (LSB)
Data Compression Log Page Fields:
Supported Parameter Codes in this page and their meanings are as follows:
Code Description Length
0001h
0002h
0003h
0004h
0005h
0006h
0007h
0008h
0009h
000Ah
000Bh
Number of entities written
Number of entities read
Number of records written
Number of records read
Megabytes to data compression
Megabytes from data compression
Megabytes to tape
Megabytes from tape
Logical entity size
Physical entity size
Uncompressed entities
4
4
4
4
4
4
4
4
4
4
4
Entities Written/Read: The total number of complete entities written to or read from the tape since the last
power-on or Clear Log operation.
Records Written/Read: The total number of records (both compressed and uncompressed) written to or read
from the tape since the last power-on or Clear Log operation.
Kilobytes to/from Data Compression: The total number of kilobytes written to or read from the tape since the
last power-on or Clear Log operation. For Kilobytes from Data Compression, this number may be greater than the
number of kilobytes transferred to the initiator due to read ahead.
Logical Entity Size: The logical size of the last entity written to or read from the tape: size = number of record in
entity × record size in bytes
Physical Entity Size: The physical size of the last entity written to or read from the tape: size = entity header
length + uncompressed data length
Uncompressed Entities: The total number of times non-ALDC entities have been encountered on the tape during
read operations since the last power-on or Clear Log operation.